Change 'MullvadDNS' to 'Mullvad' on Overview (#1267)

Author: d4rklynk

docs/tools.en.md

@@ -119,7 +119,7 @@ For your convenience, everything we recommend is listed below with a link to the
 
 ### DNS
 
-We [recommend](dns.md#recommended-providers) a number of encrypted DNS servers based on a variety of criteria, such as [MullvadDNS](https://mullvad.net/en/help/dns-over-https-and-dns-over-tls) and [Quad9](https://quad9.net/) amongst others. We recommend for you to read our pages on DNS before choosing a provider. In many cases, using an alternative DNS provider is not recommended.
+We [recommend](dns.md#recommended-providers) a number of encrypted DNS servers based on a variety of criteria, such as [Mullvad](https://mullvad.net/en/help/dns-over-https-and-dns-over-tls) and [Quad9](https://quad9.net/) amongst others. We recommend for you to read our pages on DNS before choosing a provider. In many cases, using an alternative DNS provider is not recommended.
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 [Learn more :material-arrow-right:](dns.md)